Ultrahigh lithiation dynamics of Li 4 Ti 5 O 12 as an anode material with open diffusion channels induced by chemical presodiation

Abstract Spinel lithium titanate (Li 4 Ti 5 O 12 , LTO), with the merits of safety operation voltage, stable crystal structure, and minor lattice volume changes, becomes an optimal anode material for high‐power Li‐ion batteries. However, the inherent wide bandgap and low lithiation reactivity of Li 4 Ti 5 O 12 bring about poor conductivity and lithiation dynamics, limiting its further applications. Herein, we design and prepare unique Li 4 Ti 5 O 12 anode materials with extremely low dopant content of Na + utilizing the amorphous precursors. The resultant Li 4 Na 0.008 Ti 5 O 12.004 sample (denoted as NLTO‐0.008) presents superior rate performances and cycle ability, with a reversible capacity of 149.4 mAh·g −1 at the current rate of 10.0C. NLTO‐0.008 retains the charge capacity of 151.3 mAh·g −1 with a capacity loss of 0.5% after 1000 cycles at the current rate of 1.0C (charge) /10.0C (discharge). The kinetic studies furtherly demonstrate that the lithiation reaction energy and diffusion energy barrier decrease by 28.8% and 30%, respectively. Crystal structure analysis indicates that Na + occupies the 16d Li site and forms distorted LiO 4 tetrahedron and TiO 6 octahedron. This lattice distortion forms open diffusion channels, thus enhancing the Li + diffusion dynamics and decreasing the lithiation reaction energy barrier for Li 4 Ti 5 O 12 . Therefore, the pre‐sodiation strategy may arouse great interest in understanding and developing intercalation‐type transition‐metal‐based electrode materials in high‐power lithium‐ion batteries.